German geometer who was a brilliant student and was awarded his Ph.D. at the age of 22. He then became professor of
mathematics at the Gymnasium at Erlangen and published three important mathematics paper. He also published a book
containing many geometrical gems, including what is now known as Feuerbach's theorem, 
in 1822.
Feuerbach discovered the nine-point circle of a triangle (1822) (sometimes called incorrectly the Euler
circle). He also proved that the nine point circle touches the inscribed and three escribed circles of the triangle. The
point where the incircle and the nine point circle touch is now called the Feuerbach point. Moreover,
in 1827 he introduced homogeneous coordinates, independently of Möbius.
Feuerbach, K. Eigenschaften einiger merkwürdigen Punkte des geradlinigen Dreiecks und weiterer durch sie bestimmten Linien und Figuren. Eine analytisch-trigonometrische Abhandlung.
Nürnberg, Germany: 1822.
Feuerbach, K. "Einleitung zu dem Werke Analysis der dreieckigen Pyramide durch die Methode der Coordinaten und Projectionen. Ein Beytrag zu der analytischen Geometrie."
Isis (Jena) 6, 565, 1826.
Feuerbach, K. Grundriss zu analytischen Untersuchungen der dreieckigen Pyramide. Nuremberg, 1827.
Fuhrmann, W. Synthetische Beweise Planimetrische Sätze. Berlin, 1890.
Guggenbuhl, L. "Karl Wilhelm Feuerbach, Mathematician." Appendix in Pedoe, D. Circles: A Mathematical View, rev. ed..
Washington, DC: Math. Assoc. Amer., pp. 89-100, 1995.
